What Is Vitamin K?
Vitamin K is an important nutrient that is necessary for many bodily functions, including bone metabolism and blood sugar control. Vitamin K is divided into two primary types: vitamin K1 (phylloquinone) and vitamin K2 (menaquinone).
Vitamin K1 is found in large amounts in leafy green plants and is the most common form of the vitamin. Vitamin K2 is found in animal products and fermented foods. It is not found in plant foods.
Vitamin B12 is found in foods including meat, dairy, and natto. Good bacteria in your gut help produce this nutrient.
When you have a healthy and well-balanced diet, you are unlikely to have a deficiency of vitamin K. This is because it’s plentiful in healthy whole foods.
Ultra-processed foods and refined sugars have very little vitamin K. If you eat a lot of foods that are poor in nutrients, you may not get enough of the key vitamins you need from your diet.
Vitamin K is essential for normal blood clotting, bone health, and protecting against tooth decay. A deficiency in vitamin K can lead to easy bruising, bleeding, tooth decay, and problems with bone health. This is why you need to include foods that are rich in vitamin K in your meals.
Vitamin K comes in many different forms. There are two types of vitamin K that we get from our diet: vitamin K1 and vitamin K2.
Vitamin K1 is also referred to as phytonadione. Vitamin K2 is referred to as menaquinone. Vitamin K3 is a synthetic form of vitamin K known as menadione.
Here’s a breakdown of the different types of vitamin K and how to get them from vitamin K foods or dietary supplements:
- Vitamin K1 is mostly found in vegetables, while vitamin K2 is found in fermented dairy products and is also produced by the bacteria in our guts.
- While vitamin K1 is found in plant foods that are very healthy for many reasons — such as leafy greens like spinach, kale, broccoli, and cabbage — it’s vitamin K2 that seems to be most beneficial for protecting the heart.
- In fact, vitamin K2 seems to be more effective than vitamin K1 at preventing and reversing arterial calcifications that lead to heart-related problems.
- The best way to get the daily requirement of both types is by eating a variety of whole vitamin K foods, including green plant foods and raw, fermented dairy products (like yogurt or raw cheese), fish and eggs that provide vitamin K2.
- Additionally, there is a synthetic version known as vitamin K3. However, it’s best to eat plenty of whole foods that are high in vitamin K and other important nutrients instead of relying on dietary supplements.
Top Vitamin K Foods
A list of food options that contain vitamin K can be found online. This vitamin is found in green vegetables, fruits, probiotic foods and animal products, which means you can meet your needs through a healthy and well-balanced diet.
Here are a few of the top vitamin K food sources:
- Kale — ½ cup cooked: 531 micrograms (over 100 percent DV)
- Spinach — ½ cup cooked: 445 micrograms (over 100 percent DV)
- Turnip greens — ½ cup cooked: 265 micrograms (over 100 percent DV)
- Dandelion greens — ½ cup raw: 214 micrograms (over 100 percent DV)
- Mustard greens — ½ cup cooked: 210 micrograms (over 100 percent DV)
- Swiss chard — ½ cup raw: 150 micrograms (over 100 percent DV)
- Brussels sprouts — ½ cup cooked: 109 micrograms (91 percent DV)
- Spring onions (scallions) — ½ cup raw: 103 micrograms (86 percent DV)
- Cabbage — ½ cup cooked: 81.5 micrograms (68 percent DV)
- Beef liver — 1 slice — 72 micrograms (60 percent DV)
- Kiwi — 1 cup — 71 micrograms (59 percent DV)
- Chicken breast — 3 ounces cooked — 51 micrograms (43 percent DV)
- Broccoli — ½ cup raw: 46 micrograms (38 percent DV)
- Avocado — 1 cup — 31.5 micrograms (26 percent DV)
- Blackberries — 1 cup — 29 micrograms (24 percent DV)
- Blueberries — 1 cup — 29 micrograms (24 percent DV)
- Natto — 3.5 ounces — 23 micrograms (19 percent DV)
- Prunes — 1 ounce — 17 micrograms (14 percent DV)
- Soft cheese — 1 ounce — 17 micrograms (14 percent DV)
- Kidney beans — 1 cup — 15 micrograms (13 percent DV)
- Pine nuts — 1 ounce – 15 micrograms (13 percent DV)
- Pomegranate — 1/2 cup — 14 micrograms (12 percent DV)
- Cashews — 1 ounce — 9.5 micrograms (8 percent DV)
- Ground beef — 3 ounces cooked — 8 micrograms (7 percent DV)
- Grass-fed butter —1 tablespoon — 3 micrograms (2 percent DV)
Vitamin K vs Cancer
Vitamin K in Cancer Treatment
Vitamin K2 causes cells to become different and die in many types of human cancer cell lines. There are several studies from 2008 that discuss the role of different forms of vitamin K in the treatment of cancer.
The goal of cancer researchers is to find compounds that make cancer cells destroy themselves. Vitamin K2 has been known to cause leukemia cells to self-destruct in a laboratory setting. A study published in 2008 found that vitamin K2 leads to the degradation of leukemia cells through autophagy. The scientists noted that both apoptosis and autophagy in leukemia cells could be induced by vitamin K2. In the laboratory, vitamin K2 demonstrates inhibitory effects against myeloma and lymphoma, suggesting possible applications for individuals fighting these all-too-common cancers.
Having either the hepatitis B or C virus increases your chances of developing primary liver cancer. It can also occur in those who do not have a history of the disease. A study that was published in the Journal of the American Medical Association showed that out of the people who were given vitamin K2 and who had virus-induced liver cirrhosis, less than 10% of them developed liver cancer. In patients similar to the ones in this study who were not given vitamin K2, 47% developed primary liver cancer. However, vitamin K2 decreased the risk of hepatocellular carcinoma to around 20% compared to the control group.
A study published in 2008 separated 61 primary liver cancer patients who were in remission after treatment into two groups. One group was given supplemental vitamin K2. After one year, the group that received K2 was less likely to experience a recurrence of liver cancer than the group that did not receive K2. Compared to the group that did not receive vitamin K2, the group that did receive it had a three-year survival rate of 87%.
In 2007, scientists found that vitamin K2 could help to prevent cancer by inhibiting a proinflammatory nuclear factor called NFkB. NFkB is often over-expressed in cancer cells, which use pro-inflammatory factors to develop ways of surviving attempts to kill them.
These effects alone amount to something like a time bomb in the aging population. Coumadin and other drugs that antagonize vitamin K not only cause bone loss and arterial calcification but also have other harmful effects on the aging population. The oral administration of anticoagulant drugs that antagonize vitamin K “drastically promoted metastasis” in a model of melanoma in mice. The promotion of metastasis was almost completely suppressed by the pre-administration of vitamin K3, suggesting that these anticoagulant drugs promote metastasis by specifically antagonizing vitamin K.
Vitamins K1 and K2 are safe and effective. Vitamin K3 is potentially toxic, so its use has been limited to treating aggressive cancers. A study published in early 2008 found that vitamin k3 damages pancreatic cancer cells through several specific mechanisms. The researchers said that this action of vitamin k3 could have a positive effect on pancreatic cancer.
Vitamin K3 Drug Effective Against End-Stage Prostate Cancer
It is used to treat anemia and osteoporosis. Apatone consists of vitamin C and vitamin K3 and is used to treat anemia and osteoporosis. The FDA has granted orphan drug status to the treatment of advanced bladder cancer.
Even after entering, Apatone® remains relatively inactive until it becomes localized in the lysosomes of the cancer cells. Apatone® enters cancer cells as readily as glucose and remains relatively inactive until it is localized in the lysosomes of the cancer cells. It suppresses inflammatory responses that cancer cells use to escape destruction by chemotherapy agents. Vitamin K3 is being clinically tested in order to see if it can be used as a way to make tumor cells more sensitive to chemotherapy drugs.
In March 2008, a study on prostate cancer patients who had failed standard therapy and were given Apatone® at a dose that equaled 5,000 mg of vitamin C and 50 mg of vitamin K3 was published. The results of the study showed that in 13 out of 17 patients, the PSA velocity decreased and the time it took PSA to double also increased. 15 patients continued treatment with Apatone®, and of those, only 1 death occurred after 14 months. The doctors concluded that Apatone® had the potential to delay the progression of biochemical markers in a group of end stage prostate cancer patients.5
In 2008, many studies were published showing that vitamins K2 and K3 could help prevent and treat cancer.
Cancer Patients Prone to Vitamin K Deficiency
Many cancer patients are malnourished from the disease itself or from the side effects of chemotherapy, such as nausea and poor appetite. 45 out of every 100 patients experience hemorrhagic (bleeding) side effects.
In order to establish the vitamin K status of advanced cancer patients receiving palliative care, doctors conducted a study. This is because a lack of vitamin K can lead to bleeding.
The findings showed that 22% of cancer patients were deficient in vitamin K1, which is considered below the lower limit of the reference range (below 0.33 nmol/L of blood).
A whopping 78% of cancer patients studied showed signs of a vitamin K deficiency, as shown by high levels of a protein that vitamin K normally would have carboxylated.
After studying patients with advanced cancer, the doctors concluded that they are more likely to be deficient in vitamin K. They recommended that blood tests should be done to monitor vitamin K status, so that an increased risk of bleeding can be avoided.
Supplements and Dosage
You can find this important nutrient in many places, not just in supplements.
Vitamin K tablets can be bought separately or in combination with other vitamins and nutrients such as calcium, magnesium, or vitamin D. Most multivitamins contain vitamin K.
However, natural forms of vitamin K2, such as those found in fermented foods, are more bioavailable. Vitamin K supplements commonly use synthetic forms of vitamin K1 or vitamin K2, However, natural forms of vitamin K2, such as those found in fermented foods, are more easily absorbed by the body. Studies have shown that these forms of Vitamin K2 are well absorbed by the body. However, the synthetic form of Vitamin K2, MK-7, has a longer half-life and remains active in the body for a longer period of time.
If you take a vitamin K supplement, the amount you need depends on your age and gender. Here are the current established adequate intakes for vitamin K according to the National Institutes of Health:
- 0–6 months: 2 micrograms/day
- 7–12 months: 2.5 micrograms/day
- 1–3 years: 30 micrograms/day
- 4–8 years: 55 micrograms/day
- 9–13 years: 60 micrograms/day
Adolescents and Adults
- 14–18 years: 75 micrograms/day
- 19+ years: 120 micrograms/day for males, 90 micrograms/day for females
Risks and Side Effects
Although it is generally safe to take vitamin K supplements, pregnant and breastfeeding women should avoid taking supplements that provide a higher amount than the recommended daily allowance.
If you have had a stroke, a heart attack, or problems with blood clotting, talk to your doctor before taking any supplements.
If you are on blood thinners, you should not take a vitamin K dietary supplement. You will need to moderate your vitamin K intake. If you take warfarin, you should be careful about taking vitamin K since it can reduce the effectiveness of your medications. You should speak to your doctor or dietitian if you have any questions about which foods you should avoid while taking warfarin.
The side effects of taking supplements are not common but can include a decrease in appetite, paleness, muscle stiffness, or difficulty breathing. You should stop using the product and talk to your doctor right away if you have any of these negative side effects.
Although vitamin K is necessary for healthy blood clotting, too much of it can be harmful. The best way to get vitamin K is from food sources, and it is only safe to take it as a supplement if directed by a health professional to avoid negative effects on health.
Vitamin K was discovered in 1929, and it was initially thought that it was only required for healthy blood clotting. However, researchers have since found that vitamin K is also required for proper bone and heart health. In the past 10 years, a lot of research has been done on new areas of vitamin K metabolism, including its effects on bone and vascular health, cell growth, regulation, migration, proliferation, apoptosis, immune support, and suppression of chronic inflammatory factors.
Most conventional doctors do not know much about vitamin K and its importance to elderly patients.
The government’s recommended dose of vitamin K is very small, but it is safe for people who are not taking anticoagulant drugs to take a larger dose.
There are now forms of vitamin K that only need to be taken once a day for sustained benefits.